Green Lake has been called the “diamond gem” in Austria’s crown due to the natural phenomenon that occurs every spring when the snow melts off the surrounding rugged mountains and park benches, flowers, footbridges, trees and walking paths disappear under water. The very cold but crystal clear water becomes a hot spot for divers who want to experience the exquisite and otherworldly scene. [32 Photos, 3 Videos]

This is Grüner See (Green Lake) in Austria where every spring the ice and snow on the mountaintops melt and part of the park goes underwater; this is when the scuba divers have underwater adventurers where visitors in winter would be walking on dry land. The photographer wrote, “Two weeks ago I was able to walk over this bridge … now everything is under about 6°C (42.8°F) cold water.” Photo #1 by Wolf-Ulf Wulfrolf

Bewitched by the otherworldly beauty and glowing blue waters in the Blue Grotto sea cave, we scoured the web looking for more. We found out it was a favorite spot for a Roman emperor, has inspired artists for hundreds of years, and has become a huge tourist attraction on the Isle of Capri. [32 Photos]

Once upon a time, or the 1st century A.D., Roman Emperor Tiberius retired to the Isle of Capri, Italy, and used this beautiful Blue Grotto, a sea cave, as his personal swimming pool. Emperor Tiberius loved the Blue Grotto so much that it was his favorite nymphaeum, a temple dedicated to sea nymphs…also described as a sanctuary for water nymphs. Photo #1 by Luftphilia

If you have love on the brain, then everything can tie back to love; the reality of a place can be tinted by a whimsical and romantic notion that makes a tunnel into a tunnel of love. It was curious to see places that actually are real tunnels of love and what photographers tagged as “tunnel of love.” So tap into your inner romantic, let your imagination run wild and let your heart “see” what the photographers saw. Happy Valentine’s Day! [35 Photos, 3 Videos]

Again and again people see “tunnels of love” that a less imaginative person, or one not in love, might see only as a tunnel of some sort. However, the leafy green arches over a railway track in Ukraine make up a real Tunnel of Love. Photo #1 by Livincool

Sometimes when two people are in love and believe in happily ever after, they memorialize that commitment with a padlock, a “love lock” that is; together you lock it, then throw away the key as a symbol of a “forever together until the end of time” love. Some folks love the romantic gesture, while others regard love locks as vandalizing architecture and infrastructure. No matter how many thousands are removed, thousands upon thousands of lovers continue the phenomenon of love locks all over the world. [50 Photos]

Institut de France in Paris at night with love padlocks covering both sides of Pont des Arts pedestrian bridge…before the romantic gesture was banned and the railings were replaced with glass. Love locks can be found all around the world such as Australia, Austria, Canada, China, Czech Republic, Denmark, Finland, France, Germany, Hungary, Italy, Korea, Latvia, Lithuania, Malta, New Zealand, Poland, Russia, Servia, Solvenia, Spain, Sweden, Ukraine, United Kingdom and the USA. Photo #1 by Xynn Tii

What do you like best about roller coasters? Are your favorites the tallest, fastest, longest, steepest or most loops? Is it wooden or steel, based on various track layouts, train types or the mechanics that run it? Or is it all about the thrill? Roller coasters are ranked by height, speed, length and inversions in the Roller Coaster Database, and there are other rankings for steepness, as well as thrill seekers voting for their favorite adrenaline rush roller coaster. Although amusement parks compete to build the tallest, fastest, and longest rides, those records rarely last long before another park beats that record. Here are the Inverted, Wing Coaster, Flying, Suspended, Stand Up, Sit Down and 4th Dimension roller coaster world record holders for 2015. Buckle up and take a virtual ride on the highest ranked roller coasters in the world. [71 Photos & 23 POV Videos]

Thrill seekers have traveled thousands of miles to ride thousands of roller coasters. Although amusement parks compete to build the tallest, fastest, and longest rides, those records rarely last long before another park builds a roller coaster that beats that record. Photo #1 by James Loesch

Since we last covered Amazing Aurora Borealis and Aurora Australis in 2011, many photographers have braved extremely cold temperatures to capture swirling Northern Lights dancing across the heavens. Here are some of those exceptionally beautiful auroras that you can enjoy from the warmth of your chair instead of the snowy wilds. [50 Photos, 3 Videos]

Mount Etna, one of the 17 Decade Volcanoes and Europe’s tallest active volcano, has been putting on a great show. Adrenaline-seeking tourists have been getting up-close and personal for the rumbling and lava spewing spectacle in Italy. Even the astronauts aboard the ISS have taken note and grabbed some stunning shots. Here’s Mount Etna…[42 Photos]

After rumbling for months, Mount Etna is spewing molten lava like in this lava fountain taken in August 2014. Photo #1 by Davide Nicotra

One of the reasons photographers use tilt-shift is to make life-size locations look like photos of miniature scale models. Tilt-shift photography is not only used for miniature faking, but these miniatures reminded us of the song “He’s got the whole world in his hands.” So let’s do some virtual globe hopping to view amazing miniature worlds in which city-scapes appear like toy cities. [60 Photos]

St. Peter’s Square, Vatican City in tilt shift. This type of “tilt-shift photography” can be done either by tilting the camera lens to distort the plane of focus and shifting the lens to distort the perspective, or via software. Photo #1 by Ondablv

On the edge of the New Zealand’s Paparoa National Park, you can walk among bizarre rock formations, many that resemble stacks of pancakes. The Tasman Sea surges into undercut cavities, booms, and then seawater geysers shoot through blowholes, making the spectacular natural attraction of blowholes in Pancake Rocks a “must see” at high tide and/or storms. [45 Photos]

The west coast of New Zealand is famous for its unique natural attractions of “Pancake Rocks” and blowholes, making Dolomite Point in Punakaiki “a must see” when visiting the southern island’s coastal region. Photo #1 by Christian Mehlführer

1.5 million acres in southern Florida, dubbed Everglades National Park in 1947, were inscribed by UNESCO in 1979, and then inscribed to UNESCO’s List of World Heritage Sites in Danger in 2010. The national park protects only the southern 20% of the original Everglades, yet it is the third largest national park in the lower 48 states after Death Valley and Yellowstone. Everglades National Park is also an international treasure as one of only three locations on the globe to appear on the three big lists: World Heritage Site, International Biosphere Reserve, and Wetland of International Importance. The diversity here of wildlife, nine Everglades ecosystems and changing habitats might blow your mind. The national park protects 800 species of land and water vertebrates, over 400 bird species, more than 275 species of fish and over 20 species of snakes. Here is a look at the wild beauty of America’s Everglades. [34 Photos]

American alligators in Everglades National Park as seen from Anhinga Trail. Other popular areas for wildlife viewing — like alligators, wading birds, and other animals — include Shark Valley, the Anhinga Trail at Royal Palm, and Eco Pond in the Flamingo area. Photo #1 by Miguel Vieira

In Brazil, there is an very unusual national park in the desert. While you might expect to see rolling white sand dunes, you would not expect to see the area dotted with lagoons created by rainwater. Here’s a look at those dunes and lagoons in Lençóis Maranhenses National Park. [29 Photos]

Lençois Maranhenses is called a desert, but it’s not really. Instead paradise lagoons are hidden among the rolling white dunes. Photo #1 by LCjournal

Some folks think lenticular clouds look like a stack of pancakes, but most people think they look like “saucer clouds.” These clouds are more dense, colder, than the surrounding air, so if the ambient weather doesn’t change then it just appears to hover without moving. It’s been said that these “lennies” are a possible explanation for some reported Unidentified Flying Object (UFO) sightings. If conditions are “just right,” lenticular clouds can form about anywhere. Yet this meteorological phenomenon most often appears over mountain peaks and extinct volcanoes. Even that has been dubbed “rare.” If you live in the “flat” lands, then it’s possible you’ve never witnessed an incredible UFO cloud. Photographers love to capture them, so thanks to their hard work, here are 42 fabulous photos of lovely lenticular clouds. [42 Photos]

Lenticular clouds hang steady over the sea ice in McMurdo Sound. But photographers don’t have to freeze in Antarctica to capture this dramatic meteorological phenomenon. Photo #1 by Deven Stross